Here \(\nu \)  is the Poisson's ratio, which is set to 0.33 in this study. \(\lambda \)  depends on the aspect ratio of the cross section. For \(w/t \!=\! 20\) , we have \(\lambda \!=\! 0.3228\)  [1]}.
For the creased annuli, we clamp the middle of one segment at the origin of a Cartesian coordinate, with \(\mathbf {d_1}\) , \(\mathbf {d_2}\) , and \(\mathbf {d_3}\)  aligned to \(z\) , \(-y\) , and \(x\)  direction, respectively (Figure REF a). The boundary conditions can be summarized as
\(\begin{aligned}&x(0) =0 \,, y(0) =0\,, z(0) =0\,, q_1(0)=1 \,, q_2(0)=0\,, q_3(0)=0\,, q_4(0)=0 \,, \\&x(1) =0\,, y(1) =0\,, z(1) =0\,, q_1(1)=-1 \,, q_2(1)=0\,, q_3(1)=0\,, q_4(1)=0 \,, s(0) =0 \,.\end{aligned}\) 
